On Tue, 2015-03-17 at 13:04 -0700, Paul B. Henson wrote:
> From: Ian Kent
> Sent: Tuesday, March 17, 2015 6:37 AM
> If an indirect map has the "browse" (or ghost) option the entire map
> Direct maps must always be read completely because the direct mount
Ah, yes, we do not use the ghost option or direct maps, so I did not
consider that use case.
LOL, and understandably with that many map entries.
> I think we discussed this at the time and, given the cases, decided it
> was best for sss to read the entire map and cache it since it might need
> to be able to supply the entire map and can't know if that will be the
On the other hand, there are cases such as mine where not only is
reading the entire map unnecessary but inadvisable and practically
infeasible 8-/. For my deployment, using sssd to access autofs data in
ldap rather than autofs accessing it directly would drastically
increase the load on the LDAP server, which seems completely cross
purpose to the existence of sssd. Currently there is sporadic load as
individual entries (probably no more than 10-1000 or so in a given day,
depending on the server) are looked up. With sssd, all 120000 entries
would be pulled over on an ongoing basis throughout the day (I'm not
sure how often it refreshes its local cache).
Indeed, IIRC my large map testing showed that somewhere less than 30000
is about the practical limit for reading the entire map. There would be
other side effects in autofs spending that much time reading the the
entire map too so I don't think it will ever be possible in your case.
That's okay though, I don't really have any strong need to use sssd
for autofs. I just thought it would be interesting to look into given
the new RHEL6 support from the perspective of centralizing all LDAP
lookups into one place. Assuming there are no planned changes to the
native autofs ldap support, that meets our needs fine.
I can't change the way the lookup and read map works very much
specifically because of the problems really large maps bring. If there
are any changes made they must also cover the large map requirement.
But we haven't heard from Jakub yet, it may be possible to change sss to
lookup and read the map on demand rather than all at once. Not sure
though given I'm not familiar with the wider design of sss.